Metal-spraying pistol



Aug. 8, 1939.

SCHLUPMANN METAL-S P RAYING PISTOL Filed July 26'; 1955 2 Sheets-Sheet 1 Inventor:

Patented Aug. 8, 1939 UNITED STATES 2,168,807 METAL-SPRAYING PISTOL Heinrich Schliipmann, Berlin-Niederschoneweide, Germany Application July 2c, 1935, Serial No. 33,317

Germany July 25, 1934 2 Claims. (owl -12.2)

In the known metal spraying pistols the feed of the material to be sprayed is effected bya turbine which is driven by the *ompressed air required for actuating the pistol. Herefrom resuits the drawback that firstly the output of the turbine is only small on account of the restricted available space and, in the case of only slight resistances caused by slight differences in the thickness of most of the metal wires employed or owing to slight bends therein, drops considerably resulting in irregularity of the feeding speed of the spraying wires and consequently also in an irregular thickness of the layer of sprayed metal. Secondly an adjustment of the feeding speed in the'case of drive by turbine cannot be perfect, because there is no possibility of fine regulation and, if the air pressure feed decreases the output of the turbinedrops very considerably so that, as years or work with such a pistol have proved, the number of revolutions of the turbine greatly decreases, even in the case of quite slight difference in the wire thickness or slight bend of the wires, whereas it can then only be subsequently brought with great diificulty to the correct number of revolutions. Evenslight moisture in the conduit for the compressed air, which deposits in the form of fine drops on the blades of the turbine or narrows the air admission port, causes such a reduction in the number of revolutions that a uniformly thick layer cannot be attained.

Rotary nozzles have already been employed for the existing hand spraying pistols, which nozzles are likewise driven by an air turbine. Apart from the fact that the number of revolutions for a perfect operation. and application of .the sprayed layer is much too high, the above mentioned drawbacks are also present in this instance.

The object of the invention these drawbacks.

An embodiment of the invention is illustrated, by way of example, in the accompanying drawings, in which:-

Fig. 1 shows the spraying pistol in axial section,

Fig. 2 is a section on line IL-II of Fig. 1.

Fig. 3 is an axial section through a clutch is to overcome forming part of a mechanism for rotating the nozzle of the pistol, showing the clutch-in disengaged position.

Fig. 4'is. a similar view to Fig. 3, showing the clutch in engaged position.

5 is an end view of the clutching member. The pistol comprises a motor casing a, a gear box a and a base a".

A small electric motor b is fitted in a casing a. This motor has a hollow armature shaft 8 which carries at its lower end a worm thread-c. The pole piecesd of the electric motor have a double winding, so .that the motor can be employed either for direct or alternating current. The different metal wires to be sprayed must be fed at different speeds according to whether they are made of steel, iron, copper, bronze, aluminium, aluminium alloys, tin, zinc or the like. This is efiected either by a variable resistance, or by acentrifugal governor which regulates the speed of the motor.

The wire, not shown, isinserted in the hollow shaft 8 of the motor b and a pipe 9 secured on the base a. by a nut Ill, and is fed to the nozzle ll ofthe pistol by a mechanism which will now be described. A worm wheel e meshes with the worms on the motor shaft and drives a shaft 1. A gear wheel 9 keyed on the shaft f drives a gear 20 wheel 12 on a shaft h, a gear wheel 10 and a feed wheel Z. The gear wheel k is permanently in mesh with a gear wheel m mounted on a shaft 0, oscillatable about a pivot pin 11. by means of a support p holding the shaft 0, and which shaft Q in turn carries a feed wheel q. On the free end of the support p a blade spring 1 is secured which bears against a cam s. In the position shown in Fig. l the spring r is not under tension so that the spraying wire conducted through the hollow motor shaft 8 and between the two feed wheels 1 and q to the nozzle is not fed. The teeth of the gear wheels is and m are so long that the gear wheels remain in mesh while the feed wheels I and q are so far apart that they do not engage the wire. The cam s has a handle 8' outside the gear box a'- by which it is turned through an angle of degrees to put tension on the spring r which now causes the feed wheels 1 andq to engage the wire between them and feed it toward the nozzle H through the pipe 9. When the handle s is returned into its initial position, the feed is arrested while the gear wheels is and m remain in mesh. This is advantageous as com-' damaged when moving into mesh. If, however, 50

the. wheels are at a standstill, two teeth one on each of these wheels may be directly opposite one another so that it is necessary to turn one of the wheels to move the teeth into proper relative position. 55

For rotating the nozzle II, a bevel wheel t is mounted on the shaft 1; and meshes with a bevel wheel u at the upper end of a vertical shaft in the gear box a. A hollow shaft I2 is arranged in the base a" in axial alignment with the shaft 1). A pinion w is keyed on the lower end of the hollow shaft I2 and meshes with a gear wheel :r at the upper end of a sleeve 1 on the nozzle H. A pin 6 with a handle 2 is mounted to slide in the hollow shaft and at its upper end is equipped with a clutching member I mounted to slide in notches of the hollow shaft l2 and to engage a notch in the lower end of the upper shaft 1). Figs. 2 and 3 show the clutch disengaged, and Fig. 4 shows it engaged, the member I having been pushed into the notch 5 by the handle 2. By these means, the pistol, in combination with a suitable nozzle, can be used in various ways. Thus, the pistol can be employed as a hand pistol and also in conjunction with the known spraying machine as an automatic spraying machine. In combination with this machine the piston is suitable both for the metal coating of hollow bodies and also for the external spraying if an arrangement is provided for rotating the workpiece, this presenting no difliculty and consequently does not need illustration.

A bore 3 leads from the chamber 2 into an air pipe 4 through a hollow threaded plug 22. By these means a portion of the compressed air is blown into the motor and cools the same so that even heavy continuous work cannot affect the output of the motor.

Consequently the invention ensures the following advantages over the known apparatuses:--

The feeding of the spraying wire independently of the compressed air, and consequently elimination of irregularities in the spraying process caused by fluctuations in the compressed air; drive by a sufliciently strong electric motor which overcomes all obstacles caused by irregularities of the wire, without the speed of rotation fluctuating; no overheating of the motor as it is cooled by the compressed air; employment of only one type of motor for all kinds of current; all driving wheels for the wire feed remain permanently in mesh, so that damage is as far as' possible eliminated and tiresome and time-wasting engagement of the teeth is done away with; the drive for the rotary nozzle is also effected mechanically by the motor and can be engaged and disengaged so that the pistol can be used for any kind of work and is in the true sense of the word a universal'spraying pistol; the danger of the flame flashing to the interior of the pistol is eliminated.

I claim:

1. A metal spraying pistol, comprising in combination a casing, a motor at one end of said casing, a nozzle at the other end of said casing, a hollow shaft in said motor adapted to guide a metal wire to be sprayed, a train of permanently meshing gear wheels driven by said motor, a pair of feeding members operatively connected to the gear wheels and arranged to engage opposite sides of the wire for feeding it from said hollow shaft to said nozzle, means on said casing for varying the position of said feeding members with respect to the wire, a transmission gear between said train of permanently meshing gear wheels and said nozzles and arranged to rotate said nozzle, and a clutch in said transmission gear arranged to selectively disconnect and connect said nozzle with said train of gear wheels.

2. A metal spraying pistol as specified in claim 1, in which the wire feeding members are a pair of friction wheels operatively connected to spur wheels driven by the motor, an oscillatable support carrying one of said spur wheels, a spring on said support permanently maintaining said spur wheels in mesh, and means for rendering operative said wire feeding device comprising a cam arranged to exert pressure against said spring and cause said friction wheels to firmly grip the wire.

HEINRICH SCHLUPMANN. 

